Wow, I coulda swore I hear someone tell me that Metroid wasn't as big in Japan as it was in America. Apparently they didn't take into consideration that Super Metroid sold more there the here.
I Also didn't know that Metroid Prime was the highest selling Metroid. And I though Super Metroid did better than regular Metroid. (I guess because I'd never even knew about NES Metroid until a couple years ago.)
Well on topic, I guess they could add a peripheral to the next one. Like the arm cannon thingy in the game.